Process of stereotyping.



been employed.

Up to the present time the casting of stere-' UNITED STATES P T NT,orFIoE,

SIGVALD ALFRED CHRISTIAN KRISTENSEN; or soToRP PERVALBY, NEARCOPENHAGEN, DENMARK, ASSIGNOR 1T0 ANDELSSELSKABET 1NTER NATIONALTMETALLOTYPIKOMPAGNI, LIMITED, or COPENHAGEN,

DENMARK."

enema-75.-

PROCESS OF STEREOTYPING- Patented Jan. 8, 1907,

Application filed July 27, 1905. Serial No. 271,537.

.Toall whom it may concern:

\ Be it known that I, SIGVALD ALFRED Cnnis- TIAN,.KRIsTENsEN,stereotyper, a subject of theKing Valby', near Copenhagen, Denmark, haveinvented a certain new and useful Process of stereotyping, of which thefollowing is a specification.

This invention relates to theproduction of matrices for the stereotypinof type-forms, line-etchings, and half-tone b ocks or the like; and ithas for its main purpose to increase the clearness and sharpness of thematrices and their durability and make them better adapted than are thematrices heretofore used to resist the action of several castings, even.at 'gher temperatures than have heretofore otype-plates in ordinarypaper matrices has been made at temperatures ranging from 280 to 340Fahrenheit, as the common paper matrices are not able toresist highertemperatures. Alloysofsuchlowmelting-points suffer, however, from thedefect of being rather soft, a circumstance-making it necessary veryoften to givethe stereotype-plates an aftertreatment-nickel and copperplating them, for instance-em order to increase the hardness of theirsurface, and thus enable them to betterresist the pressure and wearcaused by. the printing; ut even when employing such rather lowtemperatures of cast-' mg the ordinary paper'matrices cannot be used'formore than a very few castings, (in the reproduction of type-fo'rmsperhaps two or three,) the'reason being that the repeated application ofmolten metal to the paper ma trix makes its surface brittle and urned.This drawback is especially rorninent'in the casting ofstereotype-plates or rotarypresses, because the amount ofmetal used,andconsequently also the quantity of heat contained in such metal, ishere very considerable. Ordinary paper matrices are, besldes, not verysuitable for the stereotyping of fine-line etchings, and they areespecially unfit forlstereotyping autotype's or so-called half-tone ofDenmark, residing at Sotorp per ,tionsubsequently cast therein willtherefore 'be lacking in accuracy and depth, so that the intagli-ocavities between the grains or lines may blacken the prints producedfrom the stereotype-plate. Ordinary paper matrices 'suffenfinally fromthe defect that they will not at all slip the stereotype-plate foundedtherein unless they are previously rubbed by,

graphite, powdered soapstone, or the like, which treatment will ofcourse be detrimental to their sharpness. v w

. The present invention has for its purpose to produce matrices withsuch a coating on their surface that the matrix is on thataccount'enabled '(1) to endure a considerable number of castings; (2) toresist a temperature of casting considerably higher than what has beenused heretofore, so that alloys of.

"greater hardness may be employed; to withstand bending without anydangerof breaks or cracks in the surface, (4) to take very accurateimpressions of the veryvfinest as well as of the coarsest cavities andprojections, (5) to be used as a mold without any 7 kind ofaftertreatment, such as powdering,

greasing, &c.

The solution of the special problem embodied in requirement No. 4 1ntheabove enumeration-namely, on an ordinary paper:

matrix suitable for stereotyping of typeforms to produce also the veryfinest impresv sions has been attempted by giving those parts of themixed form (types and half-tone looks) that havethe fine cavitiesvi zthe half-tone blocks a coating consist i of whiting or powdered clay,mixed, if des red, with water, which coating is then by wiping removedfrom the printing-face beforethe resse'd down into ordinary paper flongis laid on and then parts ofth'e form coated with clay or the like theimpression is, produced b means of the fine-grained substance that fil sthe fine cavi-' ties of the form and when the wet paper flong is laid onunder pressure adheres to the flong and stands out from its surfaceafter it is removed from the form. Even admitting that an impression ofthe fine relief of the form may be made in this manner, it isnevertheless notdeep or sharp enough to give a faultioo lessreproduction of the original in such a matrix. This drawback is duepartly to the fact that the substances used will shrink considerablyduring the subsequent drying, and

consequently be subject to the formation of fissures and crevices, andpartly to the circumstance that the air lodged in the cavities of theautotype cannot escape when a paste such as the one above described is aplied to the autoty e, and consequently wil prevent the paste ompenetrating to the very bottom of the cavities and from .closelyfollowingtheir sides. For thesereasons the relief becomes inaccurate and'full of fissures and also too'low. Printinglates cast in such a matrixwill-therefore be liable to blacken the prints-taken therefrom-andgenerally will not iveas sharp and clean prints as the original.

he matrices produced in the above-'described manner-will further sufferfrom other defects and drawbacks, some of which are to 1 be mentioned inthe following: The impression-surface is very easily fractured, becausechalk, clay, and the like are brittle substances,.-the grains of whichare liable to "break when the matrix is bent, or even when it is removedfrom the form after drying. Besides, it is liable to be damaged iftouched. These substances are also porous, and durin their dryingfissures have arisen. They will therefore not easily-slip the castmetal, and as they are b'rittle it happens often that the grains breakofi-when the matrix'is removed and remain in the cavities of theoriginal etching. Thisis unfortunate, partly on account of the damage tothe matrix and partly because the etching has to be carefully cleanedbefore itcan be used again.

the adhering chalk, .&c., can only be dissolved by usmg acids, and thelatter will also very ra idly attack the etching itself, espe-' cially'i' it is 'a zinc etching, and very likely I come brittle andburned-when the metal is cast therein and will endure only a very fewcastings, even at low temperatures.

Accordin to the present invention the entire face of the matrix iscoated with a metallic film, endowing it with all the desirablequalities enumerated before under headings -1-5, and the substances aswellas the process employed for this purpose insure that the matrix thusobtainedjwill'become anexact negative copy of the relief of the form'. 4f

"The substance to be applied to the form consists, according to thepresent invention, of a li uid mixture'offinely powdered orpulverizemetal. 'Such mixture may be formed of about ten per cent. of borax inwater, to

which is addedenough ungreased-casein to This cleaninis'exceedinglydifficult and can,-in' fact, on y be, made by-chemicalmeans; but

brin the mass to a pulpy condition, after whic a volatile medium, suchas alcohol, is addedto bring the mass to a liquid state. A sufficientquantity of the powdered metal may then be added.

Especially aluminium powder is eminently suitable as a metal for the purose mentioned, partly because it is easi y held in suspension in theproper amount of liquid and partly because it may in contrast to thesubstances heretofore used easily and quickly be dissolved by a weaksolution of sodium hydrate, which practically will not attack the zinc,so that even if by inadvertence a part of the'metallic skin might remainin and on a zinc etching the latter could be easily washed freelfofsuchremnants without damage to itse The method of producing such a matrixthisis placed, in the usual way, the damp paper flong, and the Wholething is then treated in the matrix-press according to the ordinarymethod used in the so-called hot stereotyping. The metallic film on theform is thus transferred to the surface of the matrix, so that when thematrix is removed from the form the film too leaves the form and adheresto the matrix, formin on its face a continuous metallic film or sunpresenting an exceedingly fine and accurate negative repro-.

duction of the form.

The great and general superiority of this process over the methodsformerly employed lsmainly due to the employment of a metallic powder asthe filling mass. The reason is that in drying this will not shrinkappreciably, and in consequence the im rint on the matrix will be justas sharp an deep as the relief of the form itself. film on account ofbeing both hard and still somewhat elastic is also highly tenacious,both against. bending of the matrix and against casual handling andwear. It is, further, proof against even much higher temperatures thanthose used in stereotyping and has a high heat-conducting power. By thiscirv cumstance is attained the advantage of being able to use in thecasting alloys of higher melting-point, and therefore greater hardness,

than those usually em loyed, whereby the necessity of subsequent yhardening the face of the stereoty e-plate, as described before. is

avoided, an besides, the heat in the metal The metallic and inconsequence the metal oured out on the metallic skin will after soidifying veryeasily slip the matrix, there being no necessity for,greasing the latter, whereby its sharpness would be diminished beforemaking the casting. Another Jvery essential feature of the invention isthe employment of the substance in a liquid state,whereby themetalpowder is allowed to settle, so as to form a: solid film ,closelyfollowing the finest cavities of the autot pe.

In the'clabms I have used the term printing-form to include all kinds oftype matter, galvanoes, etchings, half-tone etchings, and the like, theinvention being perha s of greatest importance in connection withalf-tone etchings. c

Having now particularly described and ascertaincd the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I do claim is 1. The process for making matrices for a stereotypefrom a lprinting-form, which con-' sists in coating suc form with avolatile fluid containing an adhesive substance and a metallic powder,and after drying forming a matrix or flong of paper or papier-machthereon, said coating being transferred to the said matrix and formingwhen the matrix is dried a continuous and tough metallic film or skinextending over the face thereof.

2. In the making'of matrices for a stereo-.

type wherein a flong of fibrous material is pressed onto theprinting-form, the process which consists in coating one of said deviceswith a liquid containing a fine metallic pow-.

der, and then pressing the flong and form together to formthe matrix,such coatin con stituting a part of the matrix when the atter isremoved, and forming a metallic skin extending over the face thereof.-

3. In the making of matrices for a stereotype wherein a flong of fibrousmaterial is pressed onto the printing-form, the process which consistsin coating one of said devices with a liquid containing'a fine aluminiumpowder, and then'pressing the fiongand form together -to form thematrix, such coating constituting a part of the matrix when the latteris removed, and forming a metallic film or skin extending over the facethereof.

4. A paper or papier-mach matrix for stereotyping a printing-form,having on its face a dry and solid film consisting of a metallic owderwith an adhesive as a carrier.

n witness whereof I have hereunto set my hand in presence of twowitnesses.

SIGVALD ALFRED CHRISTIAN KRISTENSEN.

Witnesses JULIUS SELEMANN, ALBERT G. MICHELSEN.

